Historical and current environmental selection on functional traits of trees in the Atlantic Forest biodiversity hotspot

Abstract

Questions How is community functional composition associated with environmental and historical factors and how is this relationship mediated by spatial and phylogenetic autocorrelation? Location Atlantic Forest of South America. Methods We compiled abundance data of 2,122 species (most trees) distributed across 281 communities, seven functional traits, and 29 environmental and historical predictors. We mapped traits using community‐weighted means, and related traits to predictors by combining the fourth‐corner and the extended RLQ approaches. Results We found that decreases in rainfall, soil nutrition, biome stability in the last 120 kyr, and the increase in thermal variability were associated with high specific leaf area (SLA) and leaf N content, and reduced leaf thickness. In addition, increased temperature and soil sand content, and low biome stability in the last 21 kyr were associated with high wood density and leaf dry matter content, and reduced maximum plant height. Tree communities rich in taxa with N‐rich thin leaves and high SLA were mostly located in semideciduous and deciduous forests (e.g., Fabaceae), while communities rich in taxa with N‐poor thick leaves and low SLA were mostly found in rain forests (e.g., Myrtaceae and Lauraceae). Species with short stature, high wood density and heavy leaves were particularly abundant in the northern part of the Atlantic Forest (e.g., Myrtaceae), whereas tall species with light wood and leaves were abundant in the south (e.g., Lauraceae). There was not a particular direction in which seed dry mass increased most in response to predictors. Conclusions Our study reinforces the view that the multifaceted nature of community assembly needs analytical approaches that integrate abundance, functional, phylogenetic, and spatial data to properly understand how environmental and historical factors determine the dominance of functional traits. The observed patterns suggest that different regions of a given biome function in different ways, and probably provide different ecosystem services.

Functional Traits Drive Dispersal Interactions Between European Waterfowl and Seeds

“…To assess whether some plant species have a higher chance of being transported by particular waterfowl species, we used RLQ (Dolédec et al, 1996) and fourth-corner analyses (Dray et al, 2014). RLQ has traditionally been recommended to evaluate univariate relationships between environmental variables and species functional traits (Almeida et al, 2018;Schack et al, 2020;Silva J. L. A. et al, 2021). We have utilized the method to look instead at the relationships between waterfowl species traits (substituting environmental variables) and plant species functional traits.…”

Mapping functional tree regions of the Atlantic Forest: how much is left and opportunities for conservation

“…The CWM traits of specific leaf area (mm 2 mg -1 ), leaf dry matter content (g g -1 ), leaf nitrogen content (mg g -1 ), leaf thickness (mm), wood density (g cm -3 ), seed dry mass (mg) and maximum plant height (m) were computed based on abundance data regarding 2122 species distributed across 281 local communities. Community data were compiled from bibliographic sources and organized into the Caaporã database, which has been used in a number of recent publications on macroecological patterns of Brazilian and South American biomes (Cantidio & Souza 2019, Silva-Souza & Souza 2020, Silva et al 2021b. Further details on the use of this database in the Atlantic Forest can be found in Cantidio and Souza (2019) and Silva et al (2021b).…”

“…S2). This portion of the biome shows a particular functional trait dominance and phylogenetic composition (Rezende et al 2020, Silva et al 2021b). Tree communities located in the Serra do Mar mountain range are dominated by species that invest in small, thick leaves in combination with tall, light-dense woods in order to deal with shade tolerance in the dense canopy of productive forests (Silva et al 2021b).…”

“…This study used seven interpolated maps of leaf, wood, seed and plant size variation across the entire Atlantic Forest generated by Silva et al (2021b), which represent spatially contiguous surfaces of community-level traits weighted by species abundances, hereafter referred to as 'CWM traits'. The CWM traits of specific leaf area (mm 2 mg -1 ), leaf dry matter content (g g -1 ), leaf nitrogen content (mg g -1 ), leaf thickness (mm), wood density (g cm -3 ), seed dry mass (mg) and maximum plant height (m) were computed based on abundance data regarding 2122 species distributed across 281 local communities.…”

“…Although these figures indicate challenges for the maintenance of biome biodiversity, important advances in understanding have resulted from investigations into the floristic and phylogenetic macro-structures of the Atlantic Forest (Thomas 2008, Cantidio & Souza 2019, Rezende et al 2020). However, although functional macro-structure mapping would help identify natural regions where multiple conservation efforts are either more or less needed, along with taxonomic and phylogenetic structures, such functional mapping is still lacking (Vitória et al 2019, Brown et al 2020, Silva et al 2021b). This study investigates the functional regions of the Atlantic Forest, evaluates the degree to which current conservation effortsrepresented by the system of protected areascover the functional heterogeneity of the biome and discusses where and how further efforts should be directed.…”